The Multi-processor Load Balance Scheduler Based On XEN

Virtualization is a key mechanism of creating a flexible and dynamic enterprise infrastructure. With the development of more powerful multi-processors, the availability of computing power increased. Also it accelerates the trend of virtualization. It can shield the complicated underlying physical environment easily, and allow sharing of the physical machine resource among different virtual machines. Moreover, virtualization could dynamically migrate virtual machine from the running physical machine to another one without interrupting. So it can provide more security and steady for enterprise infrastructure, and it is also an ideal solution to consolidate server and application for most enterprises.Xen is one of the most popular open source software. It could make several guest OS running with the similar performance in the isolated environment and sharing the physical resource such as processor. In the virtual environment, the CPU scheduling of virtual machine is based on the virtual CPU and is time-shared. SEDF is one of the default CPU schedulers in the Xen. It supports the real time application well, but doesn’t have the ability of balancing the load among multi-processors in the SMP architecture.Considering the relationship between SMP architecture and cache, this paper illustrates a new scheduler. This scheduler contains a share waiting queue, and according to the loading status of each CPU, it dynamically adjusts the scheduling order of the virtual CPU. It can choose a optimal CPU for the scheduling virtual CPU, and avoid the free of processor.The simulation results demonstrate that the improved algorithm could get better performance than SEDF under several test standard. The system throughput and completed tasks are well, and the average turnaround time and average response time are get smaller. The improved algorithm can not only decrease the performance loss of multi-processor, but also support global loading balance better and make the processor resource more fully and reasonable.